JPH0645270B2 - Heat-sensitive perforated stencil printing base paper - Google Patents

Description

The present invention relates to a heat-sensitive perforated stencil printing base paper used for stencil printing.

More specifically, the present invention does not require a composite porous support for preventing images and the like from being removed during printing, but at the time of plate making (perforation), a specific sensitivity that can maintain the tactile sensitivity / resolution of the film to be made at a high level. The present invention relates to a printing base paper for stencil, which is used by laminating a backing sheet with easy release property.

[Prior art and its problems]

A conventional heat-sensitive perforated stencil printing base paper has been manufactured by irradiating a heat war from a Canon flash feeling or the like in a state where a black original is brought into close contact with the base paper film. However, in recent years
A plate-making method using a thermal head developed for thermal recording is drawing attention, and a dedicated stencil plate making machine using a line-type thermal head has been developed and is becoming popular. In any of the plate making methods, the heat-sensitive perforated stencil printing base paper generally used is of a type in which a thermoplastic resin film and a porous support are bonded together. Specifically, the commercially available base paper is 2μ polyethylene terephthalate (hereinafter PE
A film (abbreviated as T) and a Japanese paper (thin paper) having a basis weight of about 7 to 10 / mm ² are pasted together with a vinyl acetate adhesive or an ultraviolet curing adhesive.

In the base paper laminated with this commercially available Japanese paper, the Japanese paper itself is inhomogeneous and there are densely gathered parts of the fiber, and the parts that have been melted and shrunk during plate making are fused to the washi paper, preventing ink permeation during printing. In the present situation, it is impossible to print clearly in the case of characters, images and especially solid printing.

In addition, for the purpose of improving sensitivity and resolution, there is a base paper on the market that is made of synthetic fiber woven fabric (sorbet) of about 100 to 200 mesh, and it is widely used because the woven fabric is expensive. Not not.

[Problems to be solved by the invention]

There are two major problems in using a conventional heat-sensitive stencil printing base paper for making a stencil with a thermal head for a commercially available word processor or a personal computer printer and using it for stencil printing.

The first problem is that the PET film used for commercial base paper has a low thermal sensitivity and the thickness of 2μ is thin, but it is impossible to print almost clearly with the thermal head of a commercial printer. Is. This is because the PET film has a high crystal melting point (mp.256 ° C) and has a crystallinity (Xc = 40).
~ 45%) is high. At present, the fact is that no film having excellent heat sensitivity and resolution has been developed.

Next, the second problem is that when the conventional base paper is perforated from the film side with a thermal head and printing is performed by supplying printing ink from the support side as usual, the entire characters and sentences are printed upside down. Is to be done. Up to now, as a method for solving this problem, in JP-A-61-148064, a plate-making apparatus is provided with a mirror image printing function, and in JP-A-61-72591, ink is supplied from the film side. A method of printing on the support side is disclosed. The former is to improve the system itself, which is outside the scope of the present invention, which uses a printer of a word processor or a personal computer, which is now widely used, as a plate making machine. The actual situation is that smearing occurs and print quality deteriorates.

Further, JP-A-60-180891 discloses a base paper in which a porous support is bonded to a base paper only during plate making, the support is peeled off during printing, and the film alone is used for printing. . However, in this case, the film is not particularly limited, and the thickness is only 10 μm or less, preferably 1 to 6 μm. In other words, no improvement has been made to the film, only the thickness of the conventional base paper has been changed, there is a problem of perforation in the thick area of the film, and especially in the thin area of the film of less than 4 μm. In this case, considering the handling of the film alone, the tearing during plate making, the tearing during peeling of the support, and the holding strength of the bridging portion to prevent missing characters, etc., it was judged to be practically impossible. To be done.

On the other hand, as a method for improving image quality, even when an independent pattern having an opening is simply printed on the film as disclosed in Japanese Patent Laid-Open No. 61-102296, there is still a problem with heat insulation, and it is difficult to perforate effectively and high Under energy, the pixels tend to distort and are imperfect. In addition, the image was incomplete because dust was missing from the image after printing and unnecessary lines remained in the printed image. Further, there is a problem in forming a characteristic pattern on a thin film surface.

Therefore, to solve the various problems of the current situation, to improve the thermal sensitivity of the film in order to obtain a base paper excellent in resolution and sensitivity, good perforation in the thick area of the film, and
Developed a film that can be used independently by itself during printing, and by using it together with the film, it can provide optimal opening and resolution during plate making (the role of heat insulation and film holding during plate making) The present invention has been achieved as a result of various investigations aimed at developing

[Means and Actions for Solving Problems]

The present invention has a heat shrinkage stress value in the temperature range of 60 to 150 ° C. of 75 to 1200 g / mm ² , a heat shrinkage ratio of 60 to 170 ° C. of 30 to 90%, and a tensile elastic modulus of at least 75 kg / mm ² .
A stretched film made of a thermoplastic resin having a thickness of 4 to 18 μm, which is mm ² , and a convex portion to be directly or indirectly contacted with the film in the plate-making effective portion are formed in a mesh shape of 100 to 400 mesh. The convex area ratio per unit area is 5 to 35% and the height is at least 15 μ.
m and a mount having a convex portion, both of which are laminated so that they can be peeled off without substantially damaging the image at the time of printing after plate making, high resolution and high sensitivity,
This is a base paper for heat-sensitive perforation stencil printing.

Hereinafter, the present invention will be described in detail.

The stretched film made of the thermoplastic resin of the present invention has a heat shrinkage stress of at least 75 (g / mm ² ) at first, preferably 100 to 1200 (g / mm ² ), and more preferably 15
It is 0 to 1000 (g / mm ² ). This value is obtained by sampling the film in a strip shape with a width of 10 mm, setting it without loosening it to 50 mm between the chucks with strain gauges, immersing it in silicon oil heated to each temperature, and detecting the generated stress. It was measured by doing. silicon oil
When the temperature was 100 ° C or lower, the value after 10 seconds after immersion was used, and when the temperature was higher than 100 ° C, the value after 5 seconds was used. However, in the case of biaxial stretching, it is expressed as an average in the vertical and horizontal directions, and in the case of uniaxial stretching, it is the stretching direction. If the above range of values includes at least one part of the values of the measured shrinkage stress curve for each temperature, the range of the present invention is considered to be met. The above preferable value is that the measurement temperature is expressed in the range of 60 to 150 (° C), more preferably, this range is 60 to 140 (° C), further preferably 60 to 130 (° C), and particularly It is preferably 60 to 120 (° C). The position of the peak value of shrinkage stress with respect to temperature is 70 to 15
It is preferably 0 (° C.). More preferably 70-140
(° C), more preferably 70 to 130 (° C), and particularly preferably 70 to 120 (° C). The lower limit of the heat shrinkage stress value is a basic characteristic required for effectively generating perforations, which makes it difficult to effectively perforate holes by the thermal head method below.

On the other hand, when the amount exceeds the preferable upper limit, the openings tend to be widened and the film tends to be distorted, and as a result, the resolution of the image / character after printing tends to decrease. Further, the preferable temperature range in which the above-mentioned heat shrinkage stress develops is lower than the lower limit thereof, the dimensional stability of the film is lowered, or the aperture is widened or the film is distorted, and thus the resolution of image characters is lowered. It will be easier. On the other hand, if the upper limit is exceeded, the perforation sensitivity will be lowered, and it will be particularly apt to be affected by the backing paper, making it difficult to perform accurate perforation, which is not preferable.

Further, when the porous support is used without being used as in the present invention, the strength of the perforated portion is apt to be lowered. Further, it is one of the factors that make it difficult to perforate effectively in a region where the film thickness is large. If the position of the peak value of the shrinkage stress is below the lower limit, there is a problem in the dimensional stability of the film and the deterioration of the resolution, and above the upper limit, the sensitivity tends to decrease.

The heat shrinkage rate is at least 30 (%). This value is preferably 35 to 90 (%), more preferably 40 to 80
(%). This value is obtained by placing a 50 mm square film sample in a constant temperature bath set to a predetermined temperature, treating it for 10 minutes in a freely shrinking state, and then determining the amount of shrinkage of the film,
It is expressed as a percentage of the value divided by the original dimension. As in the case of the above stress, it is expressed in the vertical direction in the case of biaxial stretching, and the average value in the horizontal direction, and in the stretching direction in the case of uniaxial stretching.

The above values shall be met under any temperature condition, even if one part reaches the above value. The above preferable value is that the measurement temperature is expressed in the range of 60 to 170 (° C),
More preferably, this range is 65 to 140 (° C), further preferably 65 to 120 (° C), and particularly preferably 65 to 100 (° C).
Is. When the value of the heat shrinkage ratio is lower than the lower limit, it is difficult to effectively perforate and the sensitivity is lowered. On the other hand, above the preferred upper limit, enlargement of perforated holes and distortion of images and characters are likely to occur, and resolution tends to be lowered. Further, if the temperature at which the shrinkage ratio develops is lower than the lower limit, the dimensional stability of the film decreases, or the perforated hole expands,
Character distortion is likely to occur, and resolution is likely to decrease. On the other hand, above the upper limit, the perforation sensitivity decreases, and it becomes difficult for perforation means using a thermal head or the like to perforate a thick film.

The tensile elastic modulus is at least 75 (Kg / mm ² ), and a preferable value of this value is at least 100 (Kg / mm ² ), more preferably 125 (Kg / mm ² ), and even more preferably 150 (Kg / mm ² ). m
m ² ) or more.

Films below the lower limit of this value tend to lack the rigidity of the film, making it difficult to handle and perforate smoothly. In addition, enlargement of perforations, image distortion, etc. are likely to occur, and after peeling, after peeling from the backing paper or during printing, the film tends to stretch and the images and characters tend to be deformed (measurement method is ASTM D882- The value at 2% elongation is converted to 100% and expressed.) The film thickness is 4 to 18 μm, preferably 5
-15 μm, more preferably 6-13 μm, still more preferably 6-12 μm. Below the lower limit, deformation and omission of film images / characters, film wrinkles, and tears are likely to occur, and above the upper limit, it is difficult to effectively perforate not only the flash method but also the thermal head method as the perforation means. This is because. However, this is not the case when a means such as a laser is used.

The thermoplastic resin constituting the film is not particularly limited as long as it exhibits the above-mentioned performance, but in order to perforate in a region where the film thickness is thick, preferably a copolyester resin, more preferably low There are crystalline and non-crystalline copolyesters, more preferably substantially non-crystalline copolyesters. These are, for example, in the case of copolymerizing an alcohol component, in addition to ethylene glycol, as a component to be copolymerized, propylene glycol,
1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, neopentyl glycol,
At least one diol selected from polyethylene glycol, polytetramethylene glycol, cyclohexanedimethanol or other known ones, or in the case where the above ethylene glycol is not contained, based on any of the above, the above-mentioned other components as well. There are cases where at least one is included.

Next, when copolymerizing the acid component, in addition to terephthalic acid,
There are isophthalic acid, phthalic acid, other aromatic compounds, and dicarboxylic acids having a substituent on the aromatic ring that does not contribute to the esterification reaction.

It may also contain at least one dicarboxylic acid species selected from aliphatic dicarboxylic acid species such as succinic acid, adipic acid, etc., or other known ones. Either one of the alcohol component and the acid component may be used, or both may be used in a timely manner. As an example of a preferred combination, for example, ethylene glycol as the alcohol component and 1,4 cyclohexanedimethanol as the main component
There are those containing 0 mol% or less and copolymerized by using terephthalic acid as an acid component. In that case, a more preferable ratio of the copolymerization is 1,4-cyclohexanedimethanol is 20
˜40 mol%, more preferably about 25-36 mol%.

Next, for polyamide-based resins, the so-called nylon-6,6
6,6-10,11,12, Copolymer nylon-6-66,6-66
-610, 6-66-612 and the like are preferably those of a copolymer system, and in addition to these, a component having an aromatic ring,
Some are copolymerized. As those having an aromatic ring, there are terephthalic acid, isophthalic acid, fumaric acid and others having a substituent which does not contribute to the reaction in the nucleus. Among the above-mentioned copolymers, the aromatic ring is an example having a rigid portion in terms of molecular structure, but there are other hydrocarbon-containing saturated cyclo rings having many branches or those having a polar group. These have the effects of lowering the crystallinity and improving the elastic modulus, and the preferable upper limit of their copolymerization is 30 mol%, preferably 20 mol% or less. However, it goes without saying that a film that satisfies the above-mentioned film characteristics at the same time is selected.

Next is an ethylene-vinyl alcohol copolymer, the preferred ethylene content of which is 20 to 50 mol%. More preferably, it is 30 to 45 mol%. Alternatively, a composition in which the copolymer is modified (mixed) with 40% by weight or less of at least one polymer or copolymer selected from a nylon resin ester resin and an ionomer resin is used.

Next, a polycarbonate-based resin, preferably a polymer capable of forming a film even when mixed with another type, such as a polymer using a monomer whose softening point is lowered or a copolymer thereof, is used.
-40% by weight mixed.

Next, a copolystyrene resin, such as an acrylonitrile, an acrylate ester, a diene resin, etc., is available as a copolymer component. Acrylic acid esters are preferred.

Next, other examples include acrylic resins, vinyl chloride resins, vinylden chloride copolymer resins and the like, but any other suitable resin may be used. Further, a mixture of polymers of other types, a mixture of additives, plasticizers, auxiliaries, dyes, light absorbing substances, etc. may be used as long as they satisfy the above-mentioned characteristics. These are ASTM-D1525 (2kg at 1kg load)
The final composition has a Vicatt softening point of 40 to 150 (° C), preferably 50 to 130 (° C), and more preferably 60 to 120 (° C).

Amorphous or low crystalline polymers are preferred, but crystalline resins that can be made into a low crystalline state (level of crystallinity of 30% or less) depending on processing conditions can satisfy the above-mentioned properties. For example, there is polyethylene terephthalate resin. A preferred group of the above resins is polyester resins. Further, not only a single-layer film but also a multi-layer film is preferably used as long as it satisfies the above characteristics.

Further, the stretching may be performed by a known method so that the above-mentioned characteristics are exhibited sufficiently uniaxially or biaxially. It is preferable to draw at least 2.5 times or more in the lowest possible temperature range. It is preferably biaxial.

Next, a specific mount which is releasably laminated with the above-mentioned film and exerts a synergistic effect by sufficiently exhibiting the performance of the film, is a mesh-like that is directly or indirectly bonded to the above-mentioned film through an adhesive. It has a convex portion having a mesh structure. The protrusion has a mesh density of 100 to 400 mesh, an area ratio of the protrusion per unit area of 5 to 35%, and a height of at least 15 μm. The mesh-shaped mesh structure referred to here is one in which quadrilaterals are regularly arranged as shown in the plan view of FIG. The shape is preferably square, but in the unit length A, A'of the mesh-shaped convex portion shown in FIG. 1, the ratio of A to A'is 1 to 5, and the convex portion width a, a ′
In the above, the ratio of a to a'should be in the range of 1 to 3, and if the ratio is outside this range, anisotropy will occur during perforation, and uniform cut characters / images cannot be obtained. Further, the mesh density limited below is defined by the shorter side of A and A'when A and A'are not equal. Further, the angle α at the intersection of the convex portions is preferably about 90 ° C., but is not limited to 90 °, and the convex portion is not strictly limited to a straight line, and the film is substantially defined by four sides. Anything that can be fixed is acceptable. In that case, it is desirable to take the average value.

The reasons for limiting the shape will be described below.

First, the mesh density is suitable in the range of 100 to 400 mesh.
The lower limit is limited by the decrease in resolution, that is, the enlargement of the holes during drilling, and the upper limit is because the density becomes too high,
It is limited because the shrinkage of the film is hindered and the porosity is lowered and the sensitivity is deteriorated, and it is preferably 130 to 300 mesh, more preferably 150 to 250 mesh.

Next, the convex area ratio per unit area is represented by the symbol in FIG. 1, [(A × a ′) + {a × (A′−a ′)}] ×
It is given by 100 / A × A ', and it is necessary that this value is in the range of 5 to 35%. The lower limit is a manufacturing problem,
It is limited because it causes problems such as adhesion between the film and the backing sheet and a problem that resolution is deteriorated due to enlargement of holes during perforation. Further, the upper limit is limited because the area of the convex portion is too large, the shrinkage of the film is hindered, a large unperforated portion remains at a place to be perforated, and the printing tends to be chipped during printing.

Next, the height of the convex portion from the base must be at least 15 μm. The preferable range of this value is 25 μm or more, and more preferably 30 μm or more. The upper limit is not particularly limited, but is about 500 μm. Below the lower limit, there is a problem in heat transfer, the film in a portion other than the convex portion adheres to the base portion of the mount or the middle portion thereof due to deformation due to pressing at the time of punching, or the concave portion is caused by an adhesive. As a result, there are problems such as being buried, and sensitivity
The result is poor resolution. Above the above range, there are problems in production, breakage of convex portions, bending, thickness of base paper, and the like.

Next, the base material which holds the convex portion and constitutes the mount may be the same material as or different from the convex portion. The former includes those made of a photosensitive resist material, embossed sheets, various etched materials, and the like.

The latter includes printing, resist, embossing, and etching on a paper-, film-, sheet-, or mesh-like base material (eg, a cellulosic or synthetic fiber-based cloth, especially a non-woven fabric, knitted fabric, or paper). There is a method in which various materials are adhered or adhered as a convex portion forming material by a method or the like.

Preferably, a paper-like material (for example, synthetic paper, paper, etc.) or film, a sheet-shaped substrate (for example, polyester, polyvinyl chloride, polystyrene, etc.) on which projections are formed by a printing method, a resist method, or the like, or Laminated paper-like material with thermoplastic resin and then embossed that part, single layer of thermoplastic resin, multi-layered sheet with required parts of surface embossed, foam sheet embossed It is possible to use those having a convex portion formed by the foaming method.

The adhesive is usually selected from publicly known ones, and the above-mentioned film and backing sheet may be laminated by various methods so as not to destroy or deform images / characters at the time of peeling from the balance of adhesive strength and adhesive area. . For example, reaction hardening type,
Photocurable type, hot melt type, solvent type, emulsion / latex type, pressure sensitive type and the like.

The method of adhesion is to coat the adhesive thinly on the film surface, or to coat it in a spot-like shape, and lay the backing paper on top of it, or to coat an appropriate amount on the convex portion of the backing paper and lay it on the film. , Any other suitable method may be adopted.

The present invention comprises a base paper obtained by laminating the above film and a backing paper, using a high-sensitivity film as the film,
With a synergistic effect with a specific mount, it exhibits high sensitivity and high resolution, is a low energy source, and effectively perforates in a thick film area, and is used for a perforation method that does not require a porous support for image retention. It relates to the base paper.

The perforation method that does not require a porous support means that images and characters are represented by dots composed of a large number of substantially independent perforations, and the dots and images are handled without falling off of the images and characters.
This is to form a state in which a bridge of the resin constituting the film is formed, which is substantially regular and mesh-shaped enough to withstand an operation such as printing. The resin bridge, I, is the resin that makes up the film and is reinforced by gathering during perforation. This relates to a method of using the perforating film itself as ribs for reinforcement without causing a dust portion due to perforation as a result of effective perforation with high sensitivity. This is a region in which a film having a high sensitivity and a high resolution is used, and it is difficult to perforate effectively in the conventional case having a relatively large thickness, and it becomes possible for the first time due to a synergistic effect by using a specific mount.

The perforation means uses a material that absorbs light rays and heats up images / characters, and puts the originals expressed as dot-like raw dots on the film surface. From the mount side, high energy flash (using a xenon lamp etc.) ) May be irradiated, but in that case, there is a disadvantage that both the film and the backing sheet must be made of a material that transmits light rays. Further, a method may be considered in which the original is similarly made of a light-transmissive material and a flash light is given from the back side of the image on the original, but there are the same problems as described above. The most suitable method for the present invention is recently a lower heat source,
A so-called thermal head (sial type, line type) having a large number of fine heating elements, or the thermal head type in which an LED laser element or the like is arrayed as an optical element, or by scanning a laser beam, It is suitable for the type that performs dot-like irradiation.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The present invention uses a stretched film having specific performance, high sensitivity and high resolution, and has a lower energy than conventional punching means, and in a thick region of the film, which has been difficult to achieve in the past, By using a mount having a shape range, it is possible to achieve a high sensitivity and high resolution perforation platemaking as a synergistic effect of these, and to provide a specific base paper capable of giving high-level printing.

The direct effect is (1) the perforation specification of the film can be further enhanced.

(2) It can be handled in the thick film area, has good operability, and is unlikely to tear or wrinkle.

(3) No expensive porous support (for preventing image loss) is required, which is advantageous in terms of cost and process.

(4) It is not necessary to firmly adhere the porous support for preventing image loss to the film, and the decrease in heat sensitivity or the decrease in resolution due to the adhesion is small.

(5) Since it is not necessary to use the porous support during printing, the support lowers the resolution and causes white spots (imperfect ink rotation).
There are few phenomena such as.

(6) A system using an ordinary thermal head, a head having an optical array (such as a thermal transfer method or a thermal color developing method) can be diverted as it is, and there is no need to reverse the image.

(If the porous support is not laminated or mirror imaged if it is laminated, the support side must be the printing surface, which causes various problems.) (7) Above (4), (5) For this reason, extremely fine printing can be performed.

(8) Perforation with low energy can be performed and deterioration of the base film is small.

(9) High sensitivity enables high-speed plate making.

(10) Suitable for perforating thermal heads and lasers.

(Examples) Examples are shown below, but the present invention is not limited thereto.

Example 1 A substantially amorphous copolymer composed of terephthalic acid as an acid component and 1,4 cyclohexanedimethanol: 30 mol% and ethylene glycol: 70 mol% as an alcohol component. Polyester (Vicat softening point: 83 ° C, glass transition point 81 ° C, density 1.27
A rapidly cooled raw material consisting of g / cm ³ and an intrinsic viscosity of 0.76) was stretched at 95 ° C 4 × 4 times with a batch-type simultaneous biaxial stretching device to obtain a film of 7μ. The characteristic of this film is the heat shrinkage stress. 67
5g / mm ² (80 ℃, peak temperature 90 ℃), heat shrinkage 64%
(80 ° C.), and tensile elastic modulus was 240 kg / mm ² .

Next, as a mount, photocurable resist resin (commercially available)
Is coated on the cover film with each predetermined thickness, and the base film is further placed on the cover film, and various predetermined photomasks are used to irradiate with ultraviolet rays to cure, peel off the cover film, wash, and then post-cure. Then, a convex portion having a desired shape was formed on the base film to form a mount. Next, a commercially available adhesive made of acrylic emulsion was coated on the convex portion so that the solid thickness after drying was about 1.0 μ, and the above film was pressure-bonded to obtain a base paper.

Table 1 shows the characteristics of the prepared mount.

Next, after coating the film side of this base paper with a silicone type release agent, a commercially available thermal transfer type personal word processor (Casio word HW-700; 24 dots x 24 dots 2
Remove the cassette of the transfer ink tape (having a printing performance of 0 characters / sec), set it so that the film surface of the base paper hits the thermal head, adjust the print density of the print, and directly test the pattern ( The stencil printing machine (ideal science Co., Ltd.)
After wrapping around the printing drum of the lithograph AP7200E),
After peeling off the mount and the film, printing was performed at a printing speed of 120 sheets / min, and observations before and after that were made.

As a result, in order to adjust the punching condition of Run Nos. 1 to 6 after plate making, the results were observed with a solid print part microscope of the mount and the peeled film. There was an effective perforation in the part and a mesh-like rib structure between them, so that neither solid images nor character images would fall out. This did not fall off when the backing was peeled off, and the rib structure remained with almost no damage even after printing 2000 sheets with the printing machine. Moreover, the image was not distorted due to the deformation of the film.

In addition, the printed matter is clear, with white spots (where ink does not wrap around due to clogging of the image / text) and black spots (image / image).
The part of the film other than the character part is damaged or the part where the ink wraps around the thin ribs of the image part that reinforces it is damaged). Even when printed, it was clear and not so detrimental that it was clear, and was comparable to what was copied with a 20-dot laser printer using an electrostatic toner system. When observing the printed paper with a microscope, in the case of the toner system, it was found that a large amount of fine toner powder was scattered and adhered to the white background portion of the non-image area, particularly the peripheral area of the image, but the above-mentioned invention is completely No ink was attached to any part other than the image.

Also, Run Nos. 1, 2, 4, 5, and 6 are more sensitive and resolution than the case where 150 mesh mesh gauze (using 45 μm diameter polyester fiber) is stacked as a mount as in Comparative Example 10 described later. Both were good.

Next, in the case of Comparative Example 1, since the convex area ratio is as large as 50%, the backing paper receives heat during perforation, and the film shrinkage is hindered.・ Only printed matter with missing images could be obtained. In Comparative Example 2, since the mesh density is 70 mesh and the backing has a rough mesh, the four sides of the film are not fixed at a fine density at the time of plate making, and the hole expansion of the film is large. Was not formed, the molten film moved greatly with the movement of the thermal head, and an open portion and an unopened portion were extremely formed, and the printed matter was unclear.

Furthermore, Comparative Example 3 is a mount having a low convex portion, and the perforation property is deteriorated because the film contacts the concave portion of the mount during plate making,
No sufficient printed material was obtained. For further comparison, a commercially available stretched polyester film (crystallinity: 48
%, Mp: 258 ° C.) The same base paper using 2 μm hardly perforated.

From the above, it is clear that the combination of a film having the characteristics of the present invention and a specific mount is effective as a base paper without a support.

Example 2 As the film material, the same copolyester as in Example 1 was used in the same manner to appropriately select the stretching temperature, the stretching ratio and the film thickness to obtain a film having the characteristics shown in Table 2. (Ru
nNo. 7 to 9), and then a polyester having a low melting point containing 5 mol% of isophthalic acid in terephthalic acid as an acid component and ethylene glycol as an alcohol component is processed in the same manner as above to obtain a film having the specifications shown in the same table. It was (Ru
nNo.10). In the same manner, a film made of polyethylene terephthalate and having the same table was obtained. (Run No.11). Similarly, a film made of nylon 6-12 copolymer resin (RunN
o.12), a film (Run No. 13) consisting of an ethylene-vinyl alcohol copolymer (copolymerized with 39 mol% of ethylene) resin, using the same mount as in Run No. 1 of Example 1. Similarly, a base paper was created.

In Comparative Example 4, polyethylene terephthalate was rapidly cooled to obtain a raw film, which was stretched and heat-treated to have a crystallinity of about 35%.

In Comparative Example 5, polypropylene (mp 145 ° C., Vicat softening point: 125 ° C.) copolymerized with 3 wt% of ethylene was used, and in Comparative Example 6, an ethylene vinyl acetate copolymer having a vinyl acetate group content of 10 wt% (MI: 1.0, mp). 93 ° C., crystallinity 42%, Bicatt softening point 76 ° C.) Comparative Example 7 uses a vinylidene chloride vinyl chloride copolymer having a vinyl chloride content of 15 wt% and heat treated after stretching to stabilize the dimensions. did.

A thermal transfer type commercially available personal word processor (Canyon Word Mini CM-8: 24 x 24 dots 20 characters / se
A perforation plate-making test was carried out using c) as in Example 1. As a result, those of Run Nos. 7 to 13 were able to effectively perforate as in Example 1, and were similarly good in the same printing test. Films with a thickness of 5 μm tended to be somewhat lacking in stiffness, and thus required careful handling, but they could be used within the energy level adjustment range of the thermal head. Among them, Run No. 7 is performed at the drilling energy level Max, Run Nos. 8 and 9 are 3/5 with eye-opening, Run No. 10 is 4/5, Run No. 11 is Max, Run No. 12 Is 4/5, Run No. 13 is 4
/ 5 Well drilled at each level.

In Comparative Example 4, almost no perforation was performed even with energy Max, and the aperture ratio was about 5 to 10%, which was a level at which an image could hardly be discriminated even when printed.

Also, after plate-making, it was peeled off from the backing paper, and the part that received heat history was easy to tear.

In Comparative Example 5, the film has a low elastic modulus, is difficult to handle, is poor in perforation even with energy Max, and easily sticks to the thermal head, and the porosity is about 10%, and the hole is widened. It easily became a spider web. In addition, during printing, it was easy to tear in the process of peeling from the backing paper, and wrinkles easily formed after printing.

In Comparative Example 6, the film is very soft and easy to tear,
Even with the energy Max, only about 5% was drilled.

In Comparative Example 7, the film was soft and hardly perforated even with energy Max, and the degree was about 10 to 15%. Further, the thermal head is easy to stick, tears, expands holes, becomes non-uniform, and easily tears when peeled from the mount. Also, when used many times, the debris adhered to the thermal head tended to decompose and adhere.

Example 3 100 μm composed of the same copolyester as in Example 1
The unstretched sheet of No. 1 was heated and overlaid with a metal plate having 150 mesh-shaped recesses, and embossed on the rubber sheet. On the sheet, a mesh having a density of 150 mesh and a convex area ratio of 15% and a convex height of about 20 μm was formed. Using this backing sheet and the film of Example 1, a plate making / printing test similar to that of Example 1 was carried out, and good results were obtained.

Comparative Example Comparative Example 8 uses the same film as in Example 1 and uses a thin paper having a basis weight of 8.5 g / mm ² as the mount, and Comparative Example 9 uses kraft paper having a basis weight of 60 g / m ^2. In Comparative Example 10, 150 mesh mesh 45 μ polyester fiber gauze was used. About acrylic emulsion as an adhesive
The film surface was coated to give a dry weight of 1.5-2.5 g / m ² , and then the above mount was laminated and laminated.

Using these base papers, a plate making / printing test was conducted in the same manner as in Example 1.

In the case of Comparative Example 8, during plate-making, heat is easily absorbed by the back-up rubber portion against which the thermal head is pressed, the sensitivity is lowered, and since the fibers are irregular, the film should be held evenly from all sides. No precise drilling with the thermal head was done.

Next, in the case of Comparative Example 9, almost no opening was observed. It is considered that this is because the heat of the thermal head is received and the film cannot be contracted. Further, even if powder or the like is randomly sprinkled between the film and the paper, it is not so effective.

Further, in the case of Comparative Example 10, the platemaking printing suitability was better than that of Comparative Examples 8 and 9, but the mount of the present invention (Example 1Run
When compared with 2), both sensitivity and resolution are reduced. This is the same as that of Comparative Example 10 and the convex portion of the present invention when seen in a plan view. However, considering the cross section, the gauze has a round fiber weave even if an adhesive is applied. Since it is a cloth, the force to evenly hold the film from all sides during plate making is
Weaker than in the case of the present invention, further, the contact with the film, the present invention is more excellent in flatness, sensitivity,
It is considered that there is a clear difference in resolution.

The film of the present invention is a high-sensitivity film, and in a relatively thick region (within the scope of the claims of the present invention), the contact with the mesh-shaped convex portion as in the present invention provides heat insulation. It is considered that the film is held uniformly from all sides during punching, so that the sensitivity is improved and the punching is performed accurately.

[Brief description of drawings]

FIG. 1 is a plan view of a constituent basic unit of a mesh-shaped convex portion formed on a mount of the present invention. Where A and A'are
It is the unit length of the mesh-shaped convex portion, a and a ′ are the convex portion width, and α represents the angle at the intersection of the convex portions.

Claims (1)

[Claims] 1. A heat shrinkage stress value in the temperature range of 60 to 150 ° C. is 75 to 1200 g / mm ² , a heat shrinkage ratio at 60 to 170 ° C. is 30 to 90%, and a tensile elastic modulus is at least 75.
A stretched film made of a thermoplastic resin having a film thickness of Kg / mm ² of 4 to 18 μm, and convex portions to be directly or indirectly contacted with the film are formed in a mesh shape of 100 to 400 mesh in an effective portion of plate making. , The convex area ratio per unit area is 5 to 35%, and the height is at least 1.
A high-resolution, high-sensitivity, heat-sensitive perforation characterized by comprising a mount having a convex portion of 5 μm, which is laminated so as to be peelable without substantially damaging the image during printing after plate making. Base paper for stencil printing.